<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    #box{
      width: 300px;
      height: 300px;
      background-color: cyan;
      border-radius: 100% 0 0 0 ;
    }
    #box:nth-child(2){
      border-radius: 100% 100% 0 0 ;
    }
    #box:nth-child(3) {
      border-radius: 100% 0 100% 0;
    }
    

  </style>
</head>
<body>
  <div id="box"></div>
  <div id="box"></div>
  <div id="box"></div>
</body>
</html>